Commit | Line | Data |
---|---|---|
f8381cba TG |
1 | /* |
2 | * linux/kernel/time/tick-broadcast.c | |
3 | * | |
4 | * This file contains functions which emulate a local clock-event | |
5 | * device via a broadcast event source. | |
6 | * | |
7 | * Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de> | |
8 | * Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar | |
9 | * Copyright(C) 2006-2007, Timesys Corp., Thomas Gleixner | |
10 | * | |
11 | * This code is licenced under the GPL version 2. For details see | |
12 | * kernel-base/COPYING. | |
13 | */ | |
14 | #include <linux/cpu.h> | |
15 | #include <linux/err.h> | |
16 | #include <linux/hrtimer.h> | |
d7b90689 | 17 | #include <linux/interrupt.h> |
f8381cba TG |
18 | #include <linux/percpu.h> |
19 | #include <linux/profile.h> | |
20 | #include <linux/sched.h> | |
f8381cba TG |
21 | |
22 | #include "tick-internal.h" | |
23 | ||
24 | /* | |
25 | * Broadcast support for broken x86 hardware, where the local apic | |
26 | * timer stops in C3 state. | |
27 | */ | |
28 | ||
a52f5c56 | 29 | static struct tick_device tick_broadcast_device; |
6b954823 RR |
30 | /* FIXME: Use cpumask_var_t. */ |
31 | static DECLARE_BITMAP(tick_broadcast_mask, NR_CPUS); | |
32 | static DECLARE_BITMAP(tmpmask, NR_CPUS); | |
b5f91da0 | 33 | static DEFINE_RAW_SPINLOCK(tick_broadcast_lock); |
aa276e1c | 34 | static int tick_broadcast_force; |
f8381cba | 35 | |
5590a536 TG |
36 | #ifdef CONFIG_TICK_ONESHOT |
37 | static void tick_broadcast_clear_oneshot(int cpu); | |
38 | #else | |
39 | static inline void tick_broadcast_clear_oneshot(int cpu) { } | |
40 | #endif | |
41 | ||
289f480a IM |
42 | /* |
43 | * Debugging: see timer_list.c | |
44 | */ | |
45 | struct tick_device *tick_get_broadcast_device(void) | |
46 | { | |
47 | return &tick_broadcast_device; | |
48 | } | |
49 | ||
6b954823 | 50 | struct cpumask *tick_get_broadcast_mask(void) |
289f480a | 51 | { |
6b954823 | 52 | return to_cpumask(tick_broadcast_mask); |
289f480a IM |
53 | } |
54 | ||
f8381cba TG |
55 | /* |
56 | * Start the device in periodic mode | |
57 | */ | |
58 | static void tick_broadcast_start_periodic(struct clock_event_device *bc) | |
59 | { | |
18de5bc4 | 60 | if (bc) |
f8381cba TG |
61 | tick_setup_periodic(bc, 1); |
62 | } | |
63 | ||
64 | /* | |
65 | * Check, if the device can be utilized as broadcast device: | |
66 | */ | |
67 | int tick_check_broadcast_device(struct clock_event_device *dev) | |
68 | { | |
4a93232d VP |
69 | if ((tick_broadcast_device.evtdev && |
70 | tick_broadcast_device.evtdev->rating >= dev->rating) || | |
71 | (dev->features & CLOCK_EVT_FEAT_C3STOP)) | |
f8381cba TG |
72 | return 0; |
73 | ||
c1be8430 | 74 | clockevents_exchange_device(tick_broadcast_device.evtdev, dev); |
f8381cba | 75 | tick_broadcast_device.evtdev = dev; |
6b954823 | 76 | if (!cpumask_empty(tick_get_broadcast_mask())) |
f8381cba TG |
77 | tick_broadcast_start_periodic(dev); |
78 | return 1; | |
79 | } | |
80 | ||
81 | /* | |
82 | * Check, if the device is the broadcast device | |
83 | */ | |
84 | int tick_is_broadcast_device(struct clock_event_device *dev) | |
85 | { | |
86 | return (dev && tick_broadcast_device.evtdev == dev); | |
87 | } | |
88 | ||
89 | /* | |
90 | * Check, if the device is disfunctional and a place holder, which | |
91 | * needs to be handled by the broadcast device. | |
92 | */ | |
93 | int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) | |
94 | { | |
95 | unsigned long flags; | |
96 | int ret = 0; | |
97 | ||
b5f91da0 | 98 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
f8381cba TG |
99 | |
100 | /* | |
101 | * Devices might be registered with both periodic and oneshot | |
102 | * mode disabled. This signals, that the device needs to be | |
103 | * operated from the broadcast device and is a placeholder for | |
104 | * the cpu local device. | |
105 | */ | |
106 | if (!tick_device_is_functional(dev)) { | |
107 | dev->event_handler = tick_handle_periodic; | |
6b954823 | 108 | cpumask_set_cpu(cpu, tick_get_broadcast_mask()); |
f8381cba TG |
109 | tick_broadcast_start_periodic(tick_broadcast_device.evtdev); |
110 | ret = 1; | |
5590a536 TG |
111 | } else { |
112 | /* | |
113 | * When the new device is not affected by the stop | |
114 | * feature and the cpu is marked in the broadcast mask | |
115 | * then clear the broadcast bit. | |
116 | */ | |
117 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) { | |
118 | int cpu = smp_processor_id(); | |
f8381cba | 119 | |
6b954823 | 120 | cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); |
5590a536 TG |
121 | tick_broadcast_clear_oneshot(cpu); |
122 | } | |
123 | } | |
b5f91da0 | 124 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
f8381cba TG |
125 | return ret; |
126 | } | |
127 | ||
128 | /* | |
6b954823 | 129 | * Broadcast the event to the cpus, which are set in the mask (mangled). |
f8381cba | 130 | */ |
6b954823 | 131 | static void tick_do_broadcast(struct cpumask *mask) |
f8381cba | 132 | { |
186e3cb8 | 133 | int cpu = smp_processor_id(); |
f8381cba TG |
134 | struct tick_device *td; |
135 | ||
136 | /* | |
137 | * Check, if the current cpu is in the mask | |
138 | */ | |
6b954823 RR |
139 | if (cpumask_test_cpu(cpu, mask)) { |
140 | cpumask_clear_cpu(cpu, mask); | |
f8381cba TG |
141 | td = &per_cpu(tick_cpu_device, cpu); |
142 | td->evtdev->event_handler(td->evtdev); | |
f8381cba TG |
143 | } |
144 | ||
6b954823 | 145 | if (!cpumask_empty(mask)) { |
f8381cba TG |
146 | /* |
147 | * It might be necessary to actually check whether the devices | |
148 | * have different broadcast functions. For now, just use the | |
149 | * one of the first device. This works as long as we have this | |
150 | * misfeature only on x86 (lapic) | |
151 | */ | |
6b954823 RR |
152 | td = &per_cpu(tick_cpu_device, cpumask_first(mask)); |
153 | td->evtdev->broadcast(mask); | |
f8381cba | 154 | } |
f8381cba TG |
155 | } |
156 | ||
157 | /* | |
158 | * Periodic broadcast: | |
159 | * - invoke the broadcast handlers | |
160 | */ | |
161 | static void tick_do_periodic_broadcast(void) | |
162 | { | |
b5f91da0 | 163 | raw_spin_lock(&tick_broadcast_lock); |
f8381cba | 164 | |
6b954823 RR |
165 | cpumask_and(to_cpumask(tmpmask), |
166 | cpu_online_mask, tick_get_broadcast_mask()); | |
167 | tick_do_broadcast(to_cpumask(tmpmask)); | |
f8381cba | 168 | |
b5f91da0 | 169 | raw_spin_unlock(&tick_broadcast_lock); |
f8381cba TG |
170 | } |
171 | ||
172 | /* | |
173 | * Event handler for periodic broadcast ticks | |
174 | */ | |
175 | static void tick_handle_periodic_broadcast(struct clock_event_device *dev) | |
176 | { | |
d4496b39 TG |
177 | ktime_t next; |
178 | ||
f8381cba TG |
179 | tick_do_periodic_broadcast(); |
180 | ||
181 | /* | |
182 | * The device is in periodic mode. No reprogramming necessary: | |
183 | */ | |
184 | if (dev->mode == CLOCK_EVT_MODE_PERIODIC) | |
185 | return; | |
186 | ||
187 | /* | |
188 | * Setup the next period for devices, which do not have | |
d4496b39 | 189 | * periodic mode. We read dev->next_event first and add to it |
698f9315 | 190 | * when the event already expired. clockevents_program_event() |
d4496b39 TG |
191 | * sets dev->next_event only when the event is really |
192 | * programmed to the device. | |
f8381cba | 193 | */ |
d4496b39 TG |
194 | for (next = dev->next_event; ;) { |
195 | next = ktime_add(next, tick_period); | |
f8381cba | 196 | |
d1748302 | 197 | if (!clockevents_program_event(dev, next, false)) |
f8381cba TG |
198 | return; |
199 | tick_do_periodic_broadcast(); | |
200 | } | |
201 | } | |
202 | ||
203 | /* | |
204 | * Powerstate information: The system enters/leaves a state, where | |
205 | * affected devices might stop | |
206 | */ | |
f833bab8 | 207 | static void tick_do_broadcast_on_off(unsigned long *reason) |
f8381cba TG |
208 | { |
209 | struct clock_event_device *bc, *dev; | |
210 | struct tick_device *td; | |
f833bab8 | 211 | unsigned long flags; |
9c17bcda | 212 | int cpu, bc_stopped; |
f8381cba | 213 | |
b5f91da0 | 214 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
f8381cba TG |
215 | |
216 | cpu = smp_processor_id(); | |
217 | td = &per_cpu(tick_cpu_device, cpu); | |
218 | dev = td->evtdev; | |
219 | bc = tick_broadcast_device.evtdev; | |
220 | ||
221 | /* | |
1595f452 | 222 | * Is the device not affected by the powerstate ? |
f8381cba | 223 | */ |
1595f452 | 224 | if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP)) |
f8381cba TG |
225 | goto out; |
226 | ||
3dfbc884 TG |
227 | if (!tick_device_is_functional(dev)) |
228 | goto out; | |
1595f452 | 229 | |
6b954823 | 230 | bc_stopped = cpumask_empty(tick_get_broadcast_mask()); |
9c17bcda | 231 | |
1595f452 TG |
232 | switch (*reason) { |
233 | case CLOCK_EVT_NOTIFY_BROADCAST_ON: | |
234 | case CLOCK_EVT_NOTIFY_BROADCAST_FORCE: | |
6b954823 RR |
235 | if (!cpumask_test_cpu(cpu, tick_get_broadcast_mask())) { |
236 | cpumask_set_cpu(cpu, tick_get_broadcast_mask()); | |
07454bff TG |
237 | if (tick_broadcast_device.mode == |
238 | TICKDEV_MODE_PERIODIC) | |
2344abbc | 239 | clockevents_shutdown(dev); |
f8381cba | 240 | } |
3dfbc884 | 241 | if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE) |
aa276e1c | 242 | tick_broadcast_force = 1; |
1595f452 TG |
243 | break; |
244 | case CLOCK_EVT_NOTIFY_BROADCAST_OFF: | |
aa276e1c | 245 | if (!tick_broadcast_force && |
6b954823 RR |
246 | cpumask_test_cpu(cpu, tick_get_broadcast_mask())) { |
247 | cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); | |
07454bff TG |
248 | if (tick_broadcast_device.mode == |
249 | TICKDEV_MODE_PERIODIC) | |
f8381cba TG |
250 | tick_setup_periodic(dev, 0); |
251 | } | |
1595f452 | 252 | break; |
f8381cba TG |
253 | } |
254 | ||
6b954823 | 255 | if (cpumask_empty(tick_get_broadcast_mask())) { |
9c17bcda | 256 | if (!bc_stopped) |
2344abbc | 257 | clockevents_shutdown(bc); |
9c17bcda | 258 | } else if (bc_stopped) { |
f8381cba TG |
259 | if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) |
260 | tick_broadcast_start_periodic(bc); | |
79bf2bb3 TG |
261 | else |
262 | tick_broadcast_setup_oneshot(bc); | |
f8381cba TG |
263 | } |
264 | out: | |
b5f91da0 | 265 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
f8381cba TG |
266 | } |
267 | ||
268 | /* | |
269 | * Powerstate information: The system enters/leaves a state, where | |
270 | * affected devices might stop. | |
271 | */ | |
272 | void tick_broadcast_on_off(unsigned long reason, int *oncpu) | |
273 | { | |
6b954823 | 274 | if (!cpumask_test_cpu(*oncpu, cpu_online_mask)) |
833df317 | 275 | printk(KERN_ERR "tick-broadcast: ignoring broadcast for " |
72fcde96 | 276 | "offline CPU #%d\n", *oncpu); |
bf020cb7 | 277 | else |
f833bab8 | 278 | tick_do_broadcast_on_off(&reason); |
f8381cba TG |
279 | } |
280 | ||
281 | /* | |
282 | * Set the periodic handler depending on broadcast on/off | |
283 | */ | |
284 | void tick_set_periodic_handler(struct clock_event_device *dev, int broadcast) | |
285 | { | |
286 | if (!broadcast) | |
287 | dev->event_handler = tick_handle_periodic; | |
288 | else | |
289 | dev->event_handler = tick_handle_periodic_broadcast; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Remove a CPU from broadcasting | |
294 | */ | |
295 | void tick_shutdown_broadcast(unsigned int *cpup) | |
296 | { | |
297 | struct clock_event_device *bc; | |
298 | unsigned long flags; | |
299 | unsigned int cpu = *cpup; | |
300 | ||
b5f91da0 | 301 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
f8381cba TG |
302 | |
303 | bc = tick_broadcast_device.evtdev; | |
6b954823 | 304 | cpumask_clear_cpu(cpu, tick_get_broadcast_mask()); |
f8381cba TG |
305 | |
306 | if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) { | |
6b954823 | 307 | if (bc && cpumask_empty(tick_get_broadcast_mask())) |
2344abbc | 308 | clockevents_shutdown(bc); |
f8381cba TG |
309 | } |
310 | ||
b5f91da0 | 311 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
f8381cba | 312 | } |
79bf2bb3 | 313 | |
6321dd60 TG |
314 | void tick_suspend_broadcast(void) |
315 | { | |
316 | struct clock_event_device *bc; | |
317 | unsigned long flags; | |
318 | ||
b5f91da0 | 319 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
6321dd60 TG |
320 | |
321 | bc = tick_broadcast_device.evtdev; | |
18de5bc4 | 322 | if (bc) |
2344abbc | 323 | clockevents_shutdown(bc); |
6321dd60 | 324 | |
b5f91da0 | 325 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
6321dd60 TG |
326 | } |
327 | ||
328 | int tick_resume_broadcast(void) | |
329 | { | |
330 | struct clock_event_device *bc; | |
331 | unsigned long flags; | |
332 | int broadcast = 0; | |
333 | ||
b5f91da0 | 334 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
6321dd60 TG |
335 | |
336 | bc = tick_broadcast_device.evtdev; | |
6321dd60 | 337 | |
cd05a1f8 | 338 | if (bc) { |
18de5bc4 TG |
339 | clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME); |
340 | ||
cd05a1f8 TG |
341 | switch (tick_broadcast_device.mode) { |
342 | case TICKDEV_MODE_PERIODIC: | |
6b954823 | 343 | if (!cpumask_empty(tick_get_broadcast_mask())) |
cd05a1f8 | 344 | tick_broadcast_start_periodic(bc); |
6b954823 RR |
345 | broadcast = cpumask_test_cpu(smp_processor_id(), |
346 | tick_get_broadcast_mask()); | |
cd05a1f8 TG |
347 | break; |
348 | case TICKDEV_MODE_ONESHOT: | |
349 | broadcast = tick_resume_broadcast_oneshot(bc); | |
350 | break; | |
351 | } | |
6321dd60 | 352 | } |
b5f91da0 | 353 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
6321dd60 TG |
354 | |
355 | return broadcast; | |
356 | } | |
357 | ||
358 | ||
79bf2bb3 TG |
359 | #ifdef CONFIG_TICK_ONESHOT |
360 | ||
6b954823 RR |
361 | /* FIXME: use cpumask_var_t. */ |
362 | static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS); | |
79bf2bb3 | 363 | |
289f480a | 364 | /* |
6b954823 | 365 | * Exposed for debugging: see timer_list.c |
289f480a | 366 | */ |
6b954823 | 367 | struct cpumask *tick_get_broadcast_oneshot_mask(void) |
289f480a | 368 | { |
6b954823 | 369 | return to_cpumask(tick_broadcast_oneshot_mask); |
289f480a IM |
370 | } |
371 | ||
79bf2bb3 TG |
372 | static int tick_broadcast_set_event(ktime_t expires, int force) |
373 | { | |
374 | struct clock_event_device *bc = tick_broadcast_device.evtdev; | |
1fb9b7d2 | 375 | |
d1748302 | 376 | return clockevents_program_event(bc, expires, force); |
79bf2bb3 TG |
377 | } |
378 | ||
cd05a1f8 TG |
379 | int tick_resume_broadcast_oneshot(struct clock_event_device *bc) |
380 | { | |
381 | clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); | |
b7e113dc | 382 | return 0; |
cd05a1f8 TG |
383 | } |
384 | ||
fb02fbc1 TG |
385 | /* |
386 | * Called from irq_enter() when idle was interrupted to reenable the | |
387 | * per cpu device. | |
388 | */ | |
389 | void tick_check_oneshot_broadcast(int cpu) | |
390 | { | |
6b954823 | 391 | if (cpumask_test_cpu(cpu, to_cpumask(tick_broadcast_oneshot_mask))) { |
fb02fbc1 TG |
392 | struct tick_device *td = &per_cpu(tick_cpu_device, cpu); |
393 | ||
394 | clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT); | |
395 | } | |
396 | } | |
397 | ||
79bf2bb3 TG |
398 | /* |
399 | * Handle oneshot mode broadcasting | |
400 | */ | |
401 | static void tick_handle_oneshot_broadcast(struct clock_event_device *dev) | |
402 | { | |
403 | struct tick_device *td; | |
cdc6f27d | 404 | ktime_t now, next_event; |
79bf2bb3 TG |
405 | int cpu; |
406 | ||
b5f91da0 | 407 | raw_spin_lock(&tick_broadcast_lock); |
79bf2bb3 TG |
408 | again: |
409 | dev->next_event.tv64 = KTIME_MAX; | |
cdc6f27d | 410 | next_event.tv64 = KTIME_MAX; |
6b954823 | 411 | cpumask_clear(to_cpumask(tmpmask)); |
79bf2bb3 TG |
412 | now = ktime_get(); |
413 | /* Find all expired events */ | |
6b954823 | 414 | for_each_cpu(cpu, tick_get_broadcast_oneshot_mask()) { |
79bf2bb3 TG |
415 | td = &per_cpu(tick_cpu_device, cpu); |
416 | if (td->evtdev->next_event.tv64 <= now.tv64) | |
6b954823 | 417 | cpumask_set_cpu(cpu, to_cpumask(tmpmask)); |
cdc6f27d TG |
418 | else if (td->evtdev->next_event.tv64 < next_event.tv64) |
419 | next_event.tv64 = td->evtdev->next_event.tv64; | |
79bf2bb3 TG |
420 | } |
421 | ||
422 | /* | |
cdc6f27d TG |
423 | * Wakeup the cpus which have an expired event. |
424 | */ | |
6b954823 | 425 | tick_do_broadcast(to_cpumask(tmpmask)); |
cdc6f27d TG |
426 | |
427 | /* | |
428 | * Two reasons for reprogram: | |
429 | * | |
430 | * - The global event did not expire any CPU local | |
431 | * events. This happens in dyntick mode, as the maximum PIT | |
432 | * delta is quite small. | |
433 | * | |
434 | * - There are pending events on sleeping CPUs which were not | |
435 | * in the event mask | |
79bf2bb3 | 436 | */ |
cdc6f27d | 437 | if (next_event.tv64 != KTIME_MAX) { |
79bf2bb3 | 438 | /* |
cdc6f27d TG |
439 | * Rearm the broadcast device. If event expired, |
440 | * repeat the above | |
79bf2bb3 | 441 | */ |
cdc6f27d | 442 | if (tick_broadcast_set_event(next_event, 0)) |
79bf2bb3 TG |
443 | goto again; |
444 | } | |
b5f91da0 | 445 | raw_spin_unlock(&tick_broadcast_lock); |
79bf2bb3 TG |
446 | } |
447 | ||
448 | /* | |
449 | * Powerstate information: The system enters/leaves a state, where | |
450 | * affected devices might stop | |
451 | */ | |
452 | void tick_broadcast_oneshot_control(unsigned long reason) | |
453 | { | |
454 | struct clock_event_device *bc, *dev; | |
455 | struct tick_device *td; | |
456 | unsigned long flags; | |
457 | int cpu; | |
458 | ||
79bf2bb3 TG |
459 | /* |
460 | * Periodic mode does not care about the enter/exit of power | |
461 | * states | |
462 | */ | |
463 | if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC) | |
7372b0b1 | 464 | return; |
79bf2bb3 | 465 | |
7372b0b1 AK |
466 | /* |
467 | * We are called with preemtion disabled from the depth of the | |
468 | * idle code, so we can't be moved away. | |
469 | */ | |
79bf2bb3 TG |
470 | cpu = smp_processor_id(); |
471 | td = &per_cpu(tick_cpu_device, cpu); | |
472 | dev = td->evtdev; | |
473 | ||
474 | if (!(dev->features & CLOCK_EVT_FEAT_C3STOP)) | |
7372b0b1 AK |
475 | return; |
476 | ||
477 | bc = tick_broadcast_device.evtdev; | |
79bf2bb3 | 478 | |
7372b0b1 | 479 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
79bf2bb3 | 480 | if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) { |
6b954823 RR |
481 | if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) { |
482 | cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask()); | |
79bf2bb3 TG |
483 | clockevents_set_mode(dev, CLOCK_EVT_MODE_SHUTDOWN); |
484 | if (dev->next_event.tv64 < bc->next_event.tv64) | |
485 | tick_broadcast_set_event(dev->next_event, 1); | |
486 | } | |
487 | } else { | |
6b954823 RR |
488 | if (cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) { |
489 | cpumask_clear_cpu(cpu, | |
490 | tick_get_broadcast_oneshot_mask()); | |
79bf2bb3 TG |
491 | clockevents_set_mode(dev, CLOCK_EVT_MODE_ONESHOT); |
492 | if (dev->next_event.tv64 != KTIME_MAX) | |
493 | tick_program_event(dev->next_event, 1); | |
494 | } | |
495 | } | |
b5f91da0 | 496 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
79bf2bb3 TG |
497 | } |
498 | ||
5590a536 TG |
499 | /* |
500 | * Reset the one shot broadcast for a cpu | |
501 | * | |
502 | * Called with tick_broadcast_lock held | |
503 | */ | |
504 | static void tick_broadcast_clear_oneshot(int cpu) | |
505 | { | |
6b954823 | 506 | cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask()); |
5590a536 TG |
507 | } |
508 | ||
6b954823 RR |
509 | static void tick_broadcast_init_next_event(struct cpumask *mask, |
510 | ktime_t expires) | |
7300711e TG |
511 | { |
512 | struct tick_device *td; | |
513 | int cpu; | |
514 | ||
5db0e1e9 | 515 | for_each_cpu(cpu, mask) { |
7300711e TG |
516 | td = &per_cpu(tick_cpu_device, cpu); |
517 | if (td->evtdev) | |
518 | td->evtdev->next_event = expires; | |
519 | } | |
520 | } | |
521 | ||
79bf2bb3 | 522 | /** |
8dce39c2 | 523 | * tick_broadcast_setup_oneshot - setup the broadcast device |
79bf2bb3 TG |
524 | */ |
525 | void tick_broadcast_setup_oneshot(struct clock_event_device *bc) | |
526 | { | |
07f4beb0 TG |
527 | int cpu = smp_processor_id(); |
528 | ||
9c17bcda TG |
529 | /* Set it up only once ! */ |
530 | if (bc->event_handler != tick_handle_oneshot_broadcast) { | |
7300711e | 531 | int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC; |
7300711e | 532 | |
9c17bcda TG |
533 | bc->event_handler = tick_handle_oneshot_broadcast; |
534 | clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT); | |
7300711e TG |
535 | |
536 | /* Take the do_timer update */ | |
537 | tick_do_timer_cpu = cpu; | |
538 | ||
539 | /* | |
540 | * We must be careful here. There might be other CPUs | |
541 | * waiting for periodic broadcast. We need to set the | |
542 | * oneshot_mask bits for those and program the | |
543 | * broadcast device to fire. | |
544 | */ | |
6b954823 RR |
545 | cpumask_copy(to_cpumask(tmpmask), tick_get_broadcast_mask()); |
546 | cpumask_clear_cpu(cpu, to_cpumask(tmpmask)); | |
547 | cpumask_or(tick_get_broadcast_oneshot_mask(), | |
548 | tick_get_broadcast_oneshot_mask(), | |
549 | to_cpumask(tmpmask)); | |
550 | ||
551 | if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) { | |
552 | tick_broadcast_init_next_event(to_cpumask(tmpmask), | |
553 | tick_next_period); | |
7300711e TG |
554 | tick_broadcast_set_event(tick_next_period, 1); |
555 | } else | |
556 | bc->next_event.tv64 = KTIME_MAX; | |
07f4beb0 TG |
557 | } else { |
558 | /* | |
559 | * The first cpu which switches to oneshot mode sets | |
560 | * the bit for all other cpus which are in the general | |
561 | * (periodic) broadcast mask. So the bit is set and | |
562 | * would prevent the first broadcast enter after this | |
563 | * to program the bc device. | |
564 | */ | |
565 | tick_broadcast_clear_oneshot(cpu); | |
9c17bcda | 566 | } |
79bf2bb3 TG |
567 | } |
568 | ||
569 | /* | |
570 | * Select oneshot operating mode for the broadcast device | |
571 | */ | |
572 | void tick_broadcast_switch_to_oneshot(void) | |
573 | { | |
574 | struct clock_event_device *bc; | |
575 | unsigned long flags; | |
576 | ||
b5f91da0 | 577 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
79bf2bb3 TG |
578 | |
579 | tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT; | |
580 | bc = tick_broadcast_device.evtdev; | |
581 | if (bc) | |
582 | tick_broadcast_setup_oneshot(bc); | |
b5f91da0 | 583 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
79bf2bb3 TG |
584 | } |
585 | ||
586 | ||
587 | /* | |
588 | * Remove a dead CPU from broadcasting | |
589 | */ | |
590 | void tick_shutdown_broadcast_oneshot(unsigned int *cpup) | |
591 | { | |
79bf2bb3 TG |
592 | unsigned long flags; |
593 | unsigned int cpu = *cpup; | |
594 | ||
b5f91da0 | 595 | raw_spin_lock_irqsave(&tick_broadcast_lock, flags); |
79bf2bb3 | 596 | |
31d9b393 TG |
597 | /* |
598 | * Clear the broadcast mask flag for the dead cpu, but do not | |
599 | * stop the broadcast device! | |
600 | */ | |
6b954823 | 601 | cpumask_clear_cpu(cpu, tick_get_broadcast_oneshot_mask()); |
79bf2bb3 | 602 | |
b5f91da0 | 603 | raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); |
79bf2bb3 TG |
604 | } |
605 | ||
27ce4cb4 TG |
606 | /* |
607 | * Check, whether the broadcast device is in one shot mode | |
608 | */ | |
609 | int tick_broadcast_oneshot_active(void) | |
610 | { | |
611 | return tick_broadcast_device.mode == TICKDEV_MODE_ONESHOT; | |
612 | } | |
613 | ||
3a142a06 TG |
614 | /* |
615 | * Check whether the broadcast device supports oneshot. | |
616 | */ | |
617 | bool tick_broadcast_oneshot_available(void) | |
618 | { | |
619 | struct clock_event_device *bc = tick_broadcast_device.evtdev; | |
620 | ||
621 | return bc ? bc->features & CLOCK_EVT_FEAT_ONESHOT : false; | |
622 | } | |
623 | ||
79bf2bb3 | 624 | #endif |